Acute appendicitis is the most common acute abdominal cause requiring surgery. The most common age at which it occurs is 10-20 years old. The appendix is a small appendage arising from the caecum. The most common appendix position in the UK is a retrocaecal position (behind the caecum).
Pathophysiology
Appendicitis arises when pathogens get trapped within the appendix/obstruction of the appendix.
This may be due to a faecolith, impacted stool, lymphoid hyperplasia, tumour filarial worms/parasites.
The obstruction will cause commensals in the appendix to multiply resulting in an acute inflammation. This localised inflammation coupled with reduced venous drainage, increases pressure in the appendix which results in ischaemia. The ischaemia can progress to necrosis and ultimately perforation. As the infective material is released into the peritoneal cavity to causes peritonitis.
⚠️ Risk Factors
- Family history - risk is 3x higher in members of families with a previous appendicitis (although no gene has been identified).
- Ethnicity - more common in Caucasian individuals.
- Seasonal - more common in the summer.
😷 Presentation
- Peri-umbilical pain which is dull and poorly localised (due to inflammation of the visceral peritoneum). As the inflammation progresses it moves to the RIF (due to inflammation of the parietal peritoneum) and is sharp and well localised. Pain is said to be worse upon coughing.
- Nausea
- Vomiting after the pain (not before).
- Mild fever - may be swinging in nature.
- Anorexia
- Diarrhoea/constipation.
Upon examination we may find a few things:
- Rebound tenderness.
- Percussion pain over McBurney’s point (1/3rd of the way from ASIS → umbilicus).
- Guarding
- RIF mass if there is an appendiceal abscess.
Patients may also be tachycardic and hypotensive
Some specific signs include:
- Rovsing’s sign: RIF pain when palpating the LIF.
- Psoas sign: RIF pain when extending the right hip against resistance.
It is important to note that retrocaecal appendicitis may have few signs. The psoas sign is good for a retrocaecal appendix, nevertheless.
🕵🏽♂️ Differential diagnosis
There are a few potential differentials with appendicitis:
- Gynaecological - ovarian cyst rupture, PID, ectopic pregnancy.
- Renal - ureteric stone, UTI, pyelonephritis.
- Gastrointestinal - IBD, Meckel’s diverticulum, diverticular disease, mesenteric adenitis (in children), gastroenteritis.
- Urological - testicular torsion, epididymo-orchitis.
🔍 Investigations
🥇 Appendicitis is diagnosed predominantly on clinical diagnosis. However, we can do some tests and imaging to confirm diagnosis if uncertain.
In women of child-bearing age, it is suspected pregnancy until proven otherwise. A urinary ß-hCG should be done to exclude pregnancy.
Urinalysis should be done to exclude urological or renal causes mentioned above, a pregnancy test may also be done to exclude pregnancy instead.
FBC and CRP should be checked to assess for raised inflammatory markers.
Leucocytosis (neutrophil predominant) is present in 80-90% of cases.
🧰 Management
- 🏆 Laparoscopic appendectomy is the gold standard treatment, open surgery appendectomy is not commonly done nowadays. The appendix should be sent to histopathology to assess for any malignancy. Appendectomy is the only definitive treatment. It is a medical emergency and requires urgent surgical intervention.
- IV antibiotics should be given prophylactically. Patients with perforation will require plenty of abdominal lavage.
